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1.
李新生 《地球科学与环境学报》1993,(Z2)
本文首先简述了斜坡演化过程与构造运动的关系,然后阐明了滑坡的空间分布、活动周期及活动规模与构造因素的联系。在此基础上指出:构造因素是滑坡产生的基础,对滑坡分布具宏观控制作用,并与滑坡的活动周期和活动规模密切相关,是滑坡研究及其灾害预测、预防研究工作中值得重视的重要因素。 相似文献
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云南罗平中三叠世安尼期生物群的发现及其意义 总被引:15,自引:0,他引:15
本文介绍了云南罗平地区新发现的罗平生物群的产出层位、生物面貌、保存特征、古地理位置及其研究意义。该生物群产于关岭组二段薄层泥晶灰岩中,地层对比和化石鉴定表明其时代为中三叠世安尼期,以鱼类为主,伴生有爬行类、两栖类(?)、棘皮动物、节肢动物(甲壳类、昆虫等)、双壳类、腹足类以及植物化石;化石保存完好,分布广泛,埋藏方式独特。罗平生物群无论在丰度、分异度及化石保存上都极为罕见和独特,对研究埋藏学、古生态学、古地理以及三叠纪海洋生物尤其是海生爬行类都具有极为重要的意义。 相似文献
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K.-I. Chang W.J. Teague S.J. Lyu H.T. Perkins D.-K. Lee D.R. Watts Y.-B. Kim D.A. Mitchell C.M. Lee K. Kim 《Progress in Oceanography》2004,61(2-4):105
A review is made of circulation and currents in the southwestern East/Japan Sea (the Ulleung Basin), and the Korea/Tsushima Strait which is a unique conduit for surface inflow into the Ulleung Basin. The review particularly concentrates on describing some preliminary results from recent extensive measurements made after 1996. Mean flow patterns are different in the upstream and downstream regions of the Korea/Tsushima Strait. A high velocity core occurs in the mid-section in the upstream region, and splits into two cores hugging the coasts of Korea and Japan, the downstream region, after passing around Tsushima Island located in the middle of the strait. Four-year mean transport into the East/Japan Sea through the Korea/Tsushima Strait based on submarine cable data calibrated by direct observations is 2.4 Sv (1 Sv = 106 m3 s−1). A wide range of variability occurs for the subtidal transport variation from subinertial (2–10 days) to interannual scales. While the subinertial variability is shown to arise from the atmospheric pressure disturbances, the longer period variation has been poorly understood.Mean upper circulation of the Ulleung Basin is characterized by the northward flowing East Korean Warm Current along the east coast of Korea and its meander eastward after the separation from the coast, the Offshore Branch along the coast of Japan, and the anticyclonic Ulleung Warm Eddy that forms from a meander of the East Korean Warm Current. Continuous acoustic travel-time measurements between June 1999 and June 2001 suggest five quasi-stable upper circulation patterns that persist for about 3–5 months with transitions between successive patterns occurring in a few months or days. Disappearance of the East Korean Warm Current is triggered by merging the Dok Cold Eddy, originating from the pinching-off of the meander trough, with the coastal cold water carried Southward by the North Korean Cold Current. The Ulleung Warm Eddy persisted for about 20 months in the middle of the Ulleung Basin with changes in its position and spatial scale associated with strengthening and weakening of the transport through the Korea/Tsushima Strait. The variability of upper circulation is partly related to the transport variation through the Korea/Tsushima Strait. Movements of the coastal cold water and the instability of the polar front also appear to be important factors affecting the variability.Deep circulation in the Ulleung Basin is primarily cyclonic and commonly consists of one or more cyclonic cells, and an anticyclonic cell centered near Ulleung Island. The cyclonic circulation is conjectured to be driven by a net inflow through the Ulleung Interplain Gap, which serves as a conduit for the exchange of deep waters between the Japan Basin in the northern East Sea and the Ulleung Basin. Deep currents are characterized by a short correlation scale and the predominance of mesoscale variability with periods of 20–40 days. Seasonality of deep currents is indistinct, and the coupling of upper and deep circulation has not been clarified yet. 相似文献
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场论理论在经济客体地位评价中的应用:以河南省城市地位为例 总被引:7,自引:1,他引:7
一个 经济客体地位的评价不能单从该经济客体本身来考虑,它还与评价区域周围其它观察经济客体有关,会受到其它经济客体的衬托作用。经济客全的地位应包括评价经济客体在其它经济客体的“势”和其它经济客体在评价经济客体处的“势”两部分。 相似文献
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城市地理信息系统的功能和内容 总被引:1,自引:1,他引:1
本文论述了城市地理信息系统的主要功能,进而分析了城市地理信息系统的主要内容、模型和界面。 相似文献
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INTRODUCTIONThestrataofMesoprotCrozoicandNeoproterozoicaredevelopedcompletelyinthesouthpartoftheNorthetnaplatformandconsistofthreesystems,inasCendingorder,Jixiaulan,QingbaikouanandSlman.BasedonadetailedinvestigationontheolltcropandthecomprehenSiveanalysis,wediscussthecharaCterofsequencestratigraphyandthecorrelationoftheMemo--Neoproterozoicinthearea.FnThRrsor~unCrsANDPARA~unCrsMeSO--NooprotffezoicRadonalfortigraphyThesouthernpartofNorthChinaplatformherereferstotheareasincluding… 相似文献